England head coach Eddie Jones watched on as Billy Vunipola played 80 minutes in Saracens' 27-26 defeat to Ealing Trailfinders on Saturday.
Ealing on Friday announced the signing of South African lock, former Southern Kings and Lions second-rower Bobby de Wee, who started at No 4 for the West Londoners.
The ambitious English second division side, who beat Saracens on their home patch, also have former SA Under-20, Cheetahs and Bulls forward Abongile Nonkontwana on their books.
Saracens were relegated from the English Premiership last season for repeated salary cap breaches.
Vunipola was the only England international in action for Saracens before the champions' Six Nations opener against Scotland on February 6.
It meant that the likes of England captain Owen Farrell, Elliot Daly, Maro Itoje, Jamie George and Mako Vunipola have not played since December's Autumn Nations Cup final win over France.
Jones has long believed Vunipola needs plenty of rugby to be at his best.
The 28-year-old loose-forward started all five of England's end of year internationals in 2020 after recovering from the latest in a succession of broken arm injuries.